All signatures, stamps and seals on the Documents are genuine.

The original Documents we have received are authentic and complete. Any copies we have received are complete and correspond to the originals.

The drafts of the Documents reviewed are the same as the Documents that were executed and approved.

All the parties to the Documents (other than the Bank) have been duly organised and validly exist under the laws of their respective countries of incorporation.

All the parties to the Documents (other than the Bank) have the corporate power to perform the transactions and be a party to the contracts contemplated in the Documents and the contracts have been signed by an individual or individuals who have sufficient capacity to validly and effectively bind the parties to the same and compliance with that established in the contracts is within the legal capacity of each of the parties thereto (other than the Bank).

Each person who signed the Documents on behalf of the Bank had the legal capacity (capacidad de obrar) to do so at the time.

All the documents that should have been filed with the Commercial Registry of Cantabria by the Bank had been filed and registered on or before the date of our search, and subsequent to this no other documents that bear any relation to the opinions expressed in this legal opinion have been filed or registered.

The certificates of the corporate resolutions reviewed are true and accurate and correspond to resolutions that have been validly approved in duly convened, constituted and quorate meetings.

There are no contractual or other limitations that bind any of the parties to the Documents and that are included in any document that we have not reviewed but that could affect this opinion, nor are there any agreements between any of the parties to the Documents which fully or partially annul, modify or supersede the content of the Documents.

The articles of association (estatutos sociales) of the Bank that we have reviewed are those in force on the date of this legal opinion.

The Transaction Documents and the Notes (including the Global Notes) governed by the laws of a jurisdiction other than Spain create legal, valid, binding and enforceable obligations for each party to the Transaction Documents and the Notes under such laws.

The obligations deriving from the Transaction Documents and the Notes (including the Global Notes) that must be complied with in a jurisdiction other than Spain, or that could be affected in any way by the laws of such other jurisdiction, will not be invalid or ineffective by virtue of the said laws, or contrary to its public policy.

The transactions described in, contemplated in, or financed under the Transaction Documents and the Notes are not contrary to the Bank’s corporate interest (interés social) and the Bank’s directors have not breached their duty of care (deberes de diligencia y lealtad) in relation to the transaction; and the issue of the Notes is justified in the best corporate interest (interés social) of the Bank.

(i) The centre of main interests of the Bank is located in Spain; (ii) the Bank is not unable to pay its debts as per article 2 of the Insolvency Law (Ley Concursal), which restated text was approved by Royal Legislative Decree 1/2020 of 5 May (the “Insolvency Law”); (iii) the Bank will not be unable to pay its respective debts as per article 2 of the Insolvency Law as a consequence of performing its obligations under the Transaction Documents and the Notes; (iv) no petition for insolvency (concurso) or extrajudicial settlement of payments (acuerdo extrajudicial de pagos) has been filed in relation to the Bank; (v) no insolvency or administrative receiver or insolvency mediator (mediador concursal) has been appointed, or their appointment sought, to oversee any of the assets of the Bank; (vi) the Bank does not fall under any ground for winding-up as set out in article 363 of the Spanish Companies Law (Ley de Sociedades de Capital), which restated text was approved by Royal Legislative Decree 1/2010 of 2 July; and (vii) the Bank is not in a situation that could determine the application of early intervention or resolution measures pursuant to Law 11/2015, of June 18, for the recovery and resolution of credit institutions and investment firms (Ley 11/2015, de 18 de junio, de recuperación y resolución de entidades de crédito y empresas de servicios de inversión).

The Global Notes have been issued, authenticated and deposited in the State of New York.

The Notes will be admitted to trading on the New York Stock Exchange LLC prior to their first interest payment date and will not be admitted to trading on any Spanish market.

The Notes will not be offered, distributed or sold in Spain in any manner that is inconsistent with the Prospectus.

The Notes will be originally registered with a clearing and settlement system located outside Spain that is recognized by Spanish law or by the law of another OECD country.

The Notes qualify as debt instruments pursuant to the applicable Spanish accounting rules and regulations.

Valid existence

Corporate power

Corporate approvals

In the absence of case law or even settled academic doctrine on certain matters, it is impossible to rule out the possibility that a Spanish court would have a different interpretation.

Our opinions are issued subject to the effects and outcome of transactions that may derive from insolvency, the recovery and resolution proceedings of credit institutions and investment firms, pre-insolvency mechanisms or any other similar proceedings that generally affect the rights of all or some creditors, including those that do not fall under judicial insolvency proceedings (in particular, but not limited to, transactions that may derive from the insolvency regulations with respect to claw-back actions and refinancing agreements), as well as to any principles of public policy (orden público).

The information available from the website www.rmc.es may not be entirely accurate or up to date.

We offer no opinion as to the financial or economic reasonableness of the Transaction Documents or the transaction described herein.

The information on the Bank publicly available on the website of the Spanish Central Commercial Registry (www.rmc.es), dated as of the date hereof;

a copy of the articles of association (estatutos sociales) of the Bank as publicly available at the website of the Bank (www.santander.com), dated as of the date hereof;

a copy of a notarial deed granted on 12 May 2023 before the Notary Public of Madrid Mr. Rafael Martínez Díe under the number 2,400 of his records by virtue of which, among others, the resolutions adopted by the Executive Committee of the Bank on 8 May 2023 approving the registration of the Registration Statement and the execution of the documents to which the Bank is a party in connection thereto (including the Senior Preferred Debt Base Indenture and the Subordinated Debt Base Indenture, as defined below) are raised to public

a commercial registry excerpt with respect to the Bank regarding its due existence and the current directors of the Bank issued by the Commercial Registry of Cantabria on 21 July 2023;

a copy of a notarial deed granted on 24 April 2007 before the Notary Public of Santander Mr. José María de Prada Díez under the number 1,125 of his records by virtue of which, among others, the resolutions adopted by the Board of Directors of the Bank on 26 March 2007 delegating all its powers (except those that cannot be legally delegated) on the Executive Committee are raised to public;

a copy of a notarial deed granted on 20 July 2023 before the Notary Public of Madrid Mr. Rafael Martínez Díe under the number 3,671 of his records by virtue of which the resolutions adopted by the Executive Committee of the Bank on 17 July 2023 approving the issuance of the Notes and the execution of the documents to which the Bank is a party in connection thereto are raised to public;

a copy of the minutes of decisions taken by Ms. Silvana Borgatti Casale on 31 July 2023, determining, among others, the definitive principal amount of each of the issuances and the interest rates;

a copy of the notarial deed of issuance of the Notes (escritura pública de emisión) granted on 3 August 2023, before the Notary Public of Madrid, Mr. Miguel Ruiz-Gallardón García, under the number 5,182 of his records, by the Bank;

a copy of the underwriting agreement executed on 31 July 2023 by the Bank and BofA Securities, Inc., Citigroup Global Markets Inc., Goldman Sachs Bank Europe SE, HSBC Securities (USA) Inc., J.P. Morgan Securities LLC, Jefferies LLC, Morgan Stanley & Co. LLC, RBC Capital Markets, LLC, Santander US Capital Markets LLC, TD Securities (USA) LLC and Wells Fargo Securities, LLC (the “Underwriting Agreement”);

a copy of the senior preferred debt indenture dated 8 August 2023 entered into by the Bank and The Bank of New York Mellon, London Branch, as Trustee, (the “Senior Preferred Debt Base Indenture”);

a copy of the first senior preferred supplemental indenture to the Senior Preferred Debt Base Indenture dated 8 August 2023 entered into by the Bank, the Bank of New York Mellon, London Branch, as Trustee and the Bank of New York Mellon SA/NV, Luxembourg Branch, as registrar (this document together with the Senior Preferred Debt Base Indenture, the “Senior Preferred Debt Indenture”);

the subordinated debt indenture dated 8 August 2023 entered into by the Bank and The Bank of New York Mellon, London Branch, as Trustee, (the “Subordinated Debt Base Indenture”);

the first subordinated debt supplemental indenture to the Subordinated Debt Base Indenture dated 8 August 2023 entered into by the Bank, the Bank of New York Mellon, London Branch, as Trustee and the Bank of New York Mellon SA/NV, Luxembourg Branch, as registrar (this document together with the Subordinated Debt Base Indenture, the “Subordinated Debt Indenture”);

a copy of the global notes evidencing the Notes dated 8 August 2023 (the “Global Notes”);

a copy of the Registration Statement which includes a base prospectus (the “Base Prospectus”) dated 16 May 2023;

a copy of the preliminary prospectus supplements prepared in connection with the issuance of the Notes dated 31 July 2023 (the “Preliminary Prospectus Supplements”); and

a copy of the final prospectus supplements prepared in connection with the issuance of the Notes dated 31 July 2023 (this document together with the Preliminary Prospectus Supplements, the “Prospectus Supplements”).